Storage and retrieval systems sharing a common robotic fleet between a storage grid and external workstations

ABSTRACT

A storage system features a fleet of storage/retrieval vehicles and a gridded three-dimensional structure. The structure features a gridded two-dimensional track layout on which the one or more storage/retrieval vehicles are conveyable in two directions, and a plurality of storage columns residing above or below the gridded track layout in spaced distribution throughout the two-dimensional area of the track layout. Upright shafts reside above or below the gridded track layout and provide vehicle access to the storage columns. At least one working station resides outside the two-dimensional area of the track layout, and via one or more extension tracks, is served by the same vehicles that navigate the gridded structure.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit under 35 U.S.C. 119(e) of U.S.Provisional Patent Application No. 62/682,691, filed Jun. 8, 2018, andU.S. Provisional Patent Application 62/770,788, filed Nov. 22, 2018,each of which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to automated storage andretrieval systems useful in order fulfillment environments.

BACKGROUND

Applicant's prior PCT application WO2016/172793, the entirety of whichis incorporated herein by reference, disclosed a goods-to-man storageand retrieval system employing a three-dimensional storage gridstructure in which a fleet of robotic storage/retrieval vehiclesnavigate a three-dimensional array of storage locations in whichrespective bins or other storage units are held. The storage/retrievalvehicles travel horizontally in two dimensions on both a gridded uppertrack layout disposed above the three-dimensional array of storagelocations, and a gridded lower track layout disposed at ground levelbelow the array of storage locations. The same storage/retrievalvehicles also traverse the structure in the third vertical dimensionthrough vertically upright shafts that join together the upper and lowertrack layouts. Each column of storage locations is neighboured by one ofthese upright shafts, whereby each and every storage location in thegrid is directly accessible by the storage/retrieval vehicles.

Continued development has led to numerous improvements in the systemdesign, and novel applications for same, the details of which willbecome more apparent from the following disclosure.

SUMMARY OF THE INVENTION

According to a first aspect of the invention, there is provided astorage system comprising:

a gridded three-dimensional structure comprising:

-   -   a gridded lower track layout that occupies a two-dimensional        area and on which one or more storage/retrieval vehicles are        conveyable in two directions over said two-dimensional area; and    -   a plurality of storage columns residing above the gridded lower        track layout in spaced distribution over the two-dimensional        area of said lower track layout, each column comprising a        plurality of storage locations arranged one over another and        sized to accommodate placement and storage of storage units        therein; and    -   a plurality of upright shafts residing above the gridded lower        track layout in spaced distribution over the two dimensional        area of said lower track layout, each storage column being        neighboured by a respective one of the upright shafts through        which the storage locations of said storage column are        accessible by the one or more storage/retrieval vehicles to        place or remove the storage units to or from said storage        locations of said storage column; and

at least one working station residing alongside the griddedthree-dimensional structure and outside the two-dimensional area of thelower track layout over which the storage columns and upright shafts aredistributed, said working station being joined to the gridded lowertrack layout by an extension track thereof by which said one or morestorage/retrieval vehicles is conveyable between said working stationand said lower track layout, whereby conveyance of the storage unitsbetween the storage locations and the working station is performableentirely by said one or more storage/retrieval vehicles.

According to a second aspect of the invention, there is provided astorage system comprising:

one or more storage/retrieval vehicles;

a gridded three-dimensional structure comprising:

-   -   a gridded track layout that occupies a two-dimensional area and        on which the one or more storage/retrieval vehicles are        conveyable in two directions over said two-dimensional area;    -   a plurality of storage columns residing above or below the        gridded track layout in spaced distribution throughout the        two-dimensional area of said track layout, each column        comprising a plurality of storage locations arranged one over        another and sized to accommodate placement and storage of        storage units therein; and    -   a plurality of upright shafts residing above or below the        gridded track layout in spaced distribution within the        two-dimensional area of said track layout, each storage column        being neighboured by a respective one of the upright shafts        through which the storage locations of said storage column are        accessible by the one or more storage/retrieval vehicles to        place or remove the storage units to or from said storage        locations of said storage column; and

at least one working station residing outside the two-dimensional areaof the track layout within which the storage columns and upright shaftsare distributed;

wherein conveyance of the storage units between the at least one workingstation and the storage locations in the gridded three-dimensionalstructure is performed solely by said one or more storage/retrievalvehicles.

According to a third aspect of the invention, there is provided astorage system comprising:

one or more storage/retrieval vehicles;

a three-dimensional structure comprising a three-dimensional array ofstorage locations sized to accommodate placement and storage of storageunits therein; and

at least one working station to which selected storage units from thestorage locations are conveyable by said one or more storage/retrievalvehicles;

wherein each working station comprises an enclosure through which saidone or more storage/retrieval vehicles are conveyable, and an accessopening in said enclosure through which a carried storage unit on one ofthe storage/retrieval vehicles is accessible when said vehicle reachessaid access opening of the working station.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention will now be described inconjunction with the accompanying drawings in which:

FIG. 1 is a perspective view of a three-dimensional grid structure fromApplicant's aforementioned prior PCT application, in which athree-dimensional array of storage units are contained and through whicha fleet of robotic storage/retrieval vehicles can travel in threedimensions to access each said storage units.

FIG. 2 is a perspective view of a modified three-dimensional gridstructure according to the present invention.

FIG. 3 is a simplified partial perspective view of the three-dimensionalgrid structure of FIG. 2 showing a pair of intersecting outer walls ofthe grid structure at a corner thereof from which two working stationshave been removed to reveal details of said outer walls.

FIG. 4 is an isolated perspective view of one of the working stationsfrom the three-dimensional grid of FIG. 2 from an outer side thereofthat faces outwardly from the grid.

FIG. 5 is an isolated perspective view of the working station of FIG. 4from an inner side thereof that faces inwardly into the grid.

FIG. 6 is another isolated perspective view of the inner side of theworking station of FIG. 5.

FIG. 6A is a partial closeup view of the portion of FIG. 6 marked bydetail circle A thereof.

FIG. 7 is a schematic overhead plan view of the working station of FIGS.4 to 6 and a neighbouring area of a lower track layout of thethree-dimensional grid structure at which the working station isinstalled.

FIG. 8 shows a segment of a lower track of the three-dimensional grid ofFIG. 2, along which one of the robotic storage/retrieval vehicles istravelling.

FIG. 9 is a partial closeup view of the portion of FIG. 8 marked bydetail circle A thereof.

FIG. 10 is an elevational view showing one of the roboticstorage/retrieval vehicles on the lower track of the three-dimensionalgrid at launching spot below a vertical shaft of the three-dimensionalgrid through which the robotic storage/retrieval vehicle is intended totravel upwardly.

FIG. 11 is a perspective view of the robot of FIG. 10 at the launchingspot of the lower track.

FIG. 12 is a partial closeup view of the portion of FIG. 10 marked bydetail circle A thereof.

FIG. 13 is a partial closeup view of the portion of FIG. 11 marked bydetail circle B thereof.

FIG. 14 is another closeup of the same robotic storage/retrieval vehicleand lower track intersection point as FIG. 12, but with the roboticstorage/retrieval vehicle raised up to engage with rack teeth on uprightframe members of the shaft by a lifting mechanism mounted beneath thelower track.

FIG. 15 another closeup of the same robotic storage/retrieval vehicleand lower track intersection point as FIG. 13, but with the roboticstorage/retrieval vehicle in the raised position of FIG. 14.

FIGS. 16 and 17 are top and bottom perspective views of the roboticstorage/retrieval vehicle and lifting mechanism of FIGS. 10 to 13, butshown in isolation from the lower track and upright shaft members.

FIGS. 18 and 19 are top and bottom perspective views of the roboticstorage/retrieval vehicle and lifting mechanism of FIGS. 14 and 15, butshown in isolation from the lower track and upright shaft members.

FIGS. 20 and 21 illustrate one of the robotic storage/retrieval vehiclesand a compatible storage unit transportable thereon.

FIG. 22 illustrates a sortation/buffering grid employing the samethree-dimensional grid structure and robotic storage/retrieval vehiclesas the storage systems of FIGS. 1 and 2, but with a different layout ofstations serving the grid for use in management of pre-packed shippingcontainers.

DETAILED DESCRIPTION

FIG. 1 illustrates the three-dimensional grid structure from Applicant'saforementioned prior PCT application. A gridded upper track layout 10resides in an elevated horizontal plane well above a matching griddedlower track layout situated in a lower horizontal plane close to groundlevel. Between these upper and lower track layouts is athree-dimensional array of storage locations, each holding a respectivestorage unit therein, for example in the form of open-top oropenable/closeable storage tray, bin or tote capable of holding anyvariety of goods therein. The storage locations are arranged in verticalcolumns, in which storage locations of equal footprint are aligned overone another. Each such storage column is neighboured by a vertical shaftthrough which its storage locations are accessible.

Each track layout features a set of X-direction rails lying in theX-direction of a horizontal plane and a set of Y-direction railsperpendicularly crossing the X-direction rails in the Y-direction of thehorizontal plane. The crossing rails define a horizontal reference gridof the storage system, where each horizontal grid row is delimitedbetween an adjacent pair of the X-direction rails and each horizontalgrid column is delimited between an adjacent pair of the Y-directionrails. Each intersection point between one of the horizontal gridcolumns and one of the horizontal grid rows denotes the position of arespective storage column or a respective upright shaft. In other words,each storage column and each shaft resides at a respective Cartesiancoordinate point of the reference grid at a respective area boundbetween two of the X-direction rails and two of the Y-direction rails.Each such area bound between four rails in either track layout is alsoreferred to herein as a respective “spot” of said track layout. Thethree-dimensional addressing of each storage location and associatedstorage unit in the system is completed by the given vertical level atwhich the given storage location resides within the respective column.That is, a three-dimensional address of each storage location isdictated by the horizontal grid row, horizontal grid column and verticalcolumn level of the storage location in the three-dimensional grid.

A respective upright frame member 12 spans vertically between the upperand lower track layouts at each intersection point between theX-direction and Y-direction rails, thereby cooperating with the trackrails to define a framework of the three-dimensional grid structure forcontaining and organizing the three-dimensional array of storage unitswithin this framework. As a result, each upright shaft of thethree-dimensional storage array has four vertical frame members spanningthe full height of the shaft at the four corners thereof. Each framemember has respective sets of rack teeth arranged in series in thevertical Z-direction of the three-dimensional grid on two sides of theframe member. Each shaft thus has eight sets of rack teeth in total,with two sets at each corner of the shaft, which cooperate with eightpinion wheels on the robotic storage/retrieval vehicles to enabletraversal of same between the upper and lower track layouts through theshafts of the three-dimensional grid structure. Each roboticstorage/retrieval vehicle 14 has both round conveyance wheels forconveyance of the robotic storage/retrieval vehicle over the upper andlower track layouts in a track-riding mode, and toothed pinion wheelsfor traversal of the robotic storage/retrieval vehicle through therack-equipped shafts in a shaft-traversing mode. Each pinion wheel and arespective conveyance wheel are part of a combined singular wheel unit,extendable in an outboard direction from the vehicle for use of theconveyance wheels in a track-riding mode on either track layout, andretractable in an inboard direction of the vehicle for use of the pinionwheels in a shaft-traversing mode engaging the pinion wheels with therack teeth of the upright frame members of a shaft.

The framework of the grid structure includes a respective shelf at eachstorage location to support the respective storage unit, whereby anygiven storage unit 16 can be removed from its storage location by one ofthe robotic retrieval vehicles without disrupting the storage unitsabove and below it in the same storage column. Likewise, this allows astorage unit to be returned to a prescribed location at any level in thearray. The lower gridded track layout at the bottom of thethree-dimensional grid has a number of working stations 18 distributedaround its perimeter to which the robotic retrieval vehicles 14 deliverthe storage units pulled from the storage columns. Except fordifferences explicitly described herein, the framework of thethree-dimensional grid structure, the robotic storage/retrievalvehicles, their travel over the upper and lower track layouts andthrough the shafts, and their transition between the track-riding andshaft-traversing modes are the same as described in Applicant'saforementioned prior PCT application.

FIG. 2 shows a modified form the prior three-dimensional grid structure,which once again features the upper and lower track layouts and theupright frame members that span therebetween to carry shelving at thestorage locations for support of the storage units therein, and alsocarry the rack teeth engagable by the pinion wheels of the roboticstorage/retrieval vehicles to enable vertical travel of thereof throughthe shafts. The shelving may be in the form of flanged panels or railsat the three sides of the storage column other than the fourthshaft-adjacent side that opens into the neighbouring access shaft fromwhich the robotic storage/retrieval vehicles access the storage units ofthat column, whereby this fourth open side enables insertion andwithdrawal of the retractable turret arm of each vehicle into thestorage column at to pull and push storage units into and out of thestorage column through engagement with the undersides of the storageunits.

As outlined in in Applicant's aforementioned prior PCT application, asubset of the vertical shafts located at the outer perimeter may be“up-shafts” that are dedicated for upward travel of the robotic storagevehicles therethrough from the lower track layout to the upper tracklayout after having delivered a storage unit to one of the workingstations 18, while other vertical shafts are “down-shafts” that arededicated for downward travel of the robotic storage vehiclestherethrough from the upper track layout during either retrieval of astorage unit from the three dimensional storage array, or return of astorage unit back into the three dimensional array after havingpreviously delivered the storage unit to one of the working stations 18for a picking, re-stocking or other operation.

The three-dimensional grid structure of FIG. 2 differs from that of FIG.1 in that cladding panels 20 have been added to the upright framemembers at the outer perimeter of the grid structure to create outerside walls that substantially close off all four sides of the gridstructure, thus visually concealing the interior thereof, and in thatthe upright frame members 12 include top segments 22 thereof that standupright frame the rails of the upper track members at the intersectionpoints thereof, and that obscure the upper track from sight in theparticular wide-view of the grid structure shown in FIG. 2. These topsegments of the shaft may be used for mounting of charging stationhardware by which the robotic storage/retrieval vehicles can berecharged when necessary. However, the structure and purpose of theupper track layout and the form of shafts and storage columns inside thegrid structure by the upright frame members are well documented inApplicant's prior PCT application, and thus require no detailedillustration or explanation herein.

Turning now to FIGS. 3 to 6, attention is given to the novel structureof the working stations 18 and the novel interaction therewith by therobotic storage/retrieval vehicles. In the interest of illustrativesimplification, FIG. 3 omits much of the grid structure. Shown howeverare one X-direction rail 24 and one Y-direction rail 26 of the lowertrack layout 28 that form two outer sides of the lower track layout andintersect at a respective outer corner of the grid structure. Of theremainder of the lower track layout, only the support legs 30 elevatingthese two particular rails off the ground are shown. Among the uprightframe members 12 of the grid structure, only those that stand uprightfrom two illustrated rails 24, 26 at these two outer sides of the gridstructure are shown, and the top segments 22 of these upright framemembers 12 are omitted. Around the full perimeter of the grid structure,the cladding panels 20 do not extend fully down to the lower track 28,but instead terminate in a slightly elevated relation thereover so thatbottom segments 32 of the upright frame members that attach to and standupright from the rails of the lower track layout are left uncladded.This leaves an open space 34 between the bottom segments 32 of everyadjacent pair of upright frame members 12. These open spaces 34 allowthe robotic storage/retrieval vehicles 14 to enter and exit thethree-dimensional grid structure at the lower track 28 thereof, and thustransition between the three-dimensional grid structure and the workingstations 18.

As outlined in more detail below, this enables a novel solution forgoods-to-man order fulfilment, where a robotic storage/retrieval vehiclecapable of travel in three dimensions provides the sole means of storageunit conveyance throughout an entire order picking operation, from theinitial retrieval of the storage unit from anywhere in the threedimensional space of the grid, through delivery of the storage unit tothe working station, including presentation of the storage unit to ahuman or robot picker at the working station, and subsequent return ofthe storage unit back into any three dimensional location in the grid,without the storage unit ever being offloaded from the roboticstorage/retrieval vehicle and conveyed by a separate conveyor, turntableor other transitional mechanism.

FIGS. 4 through 6 illustrate one of the working stations 18 in isolationfrom the three-dimensional storage grid. Each working station 18features a gridded lower track 36 featuring a pair of longitudinal rails38 a, 38 b running a length of the working station 18. The lower trackalso features a set of cross rails 40 a-40 f perpendicularlyinterconnecting the longitudinal rails 38 with one another at regularlyspaced internals therealong. These rails are of the same type used inthe gridded upper and lower track layouts of the three-dimensional gridstructure, and the spacing between the longitudinal rails matches thespacing between the cross rails and is equal to the inter-rail spacingemployed between the rails of the upper and lower track layouts of thegrid structure in both the X and Y directions thereof. Accordingly, thelower track of the working station can be traversed by the roboticstorage/retrieval vehicles in the same manner as the upper and lowertrack layouts of the three-dimensional grid. The lower track of theworking station is supported in slightly elevated relation above groundlevel by support legs 30 depending downward from the lower track at theintersection points of the longitudinal rails and cross rails. Thesesupport legs 30 are of the same type and height as those that supportthe lower track layout of the three-dimensional grid, whereby the lowertrack 36 of the working station resides at the same elevation as thelower track layout of three-dimensional grid structure to form acoplanar extension track extending therefrom.

The working station features a chute 42 mounted to the lower track andspanning longitudinally end-to-end thereof from a first one of thecross-rails 40 a at a first end of the longitudinal rails to a last oneof the cross-rails 40 f at a second opposing end of the longitudinalrails. The chute features a first end wall 44 standing upright from thefirst cross-rail, a second end wall 46 standing upright from the lastcross-rail in opposing and parallel relation to the first end wall, alonger outer side wall 48 spanning longitudinally between the end wallsin perpendicular relation thereto at an outer one 38 b of thelongitudinal rails, and a top cover panel 50 spanning longitudinallybetween the end walls and along the top edge of the outer side wall. Anunderside of the cover panel 50 defines an interior ceiling of the chute42, while an opposing topside of the cover panel defines an externalcountertop 50 a for exploit by human or robotic workers during picking,restocking or other work functions that may be performed at the workingstation 18.

Each square area delimited between the two longitudinal rails 38 a, 38 band any adjacent pair of the cross rails 40 a-40 f is referred to as arespective “spot” along the lower track of the working station. The spotlocated immediately adjacent the first end wall 44 of the chute 42 andbound between the first and second cross rails 40 a, 40 b at the firstend of the chute is referred to as an entrance spot S_(EN) of theworking station, as it is here that a robotic storage/retrieval vehicleenters the chute by riding onto these first and second cross rails 40 a,40 b from a respective pair of rails aligned therewith in the lowertrack layout of the grid structure. At the opposing second end of thechute, the spot located immediately adjacent the second end wall 46between the second-last and last cross rails 40 e, 40 f is referred toas an exit spot S_(X), as it is here that the robotic storage/retrievalvehicle exits the chute and re-enters the three-dimensional grid byriding off these last and second-last cross-rails onto anotherrespective pair of rails aligned therewith in the lower track layout ofthe grid structure.

Referring to FIG. 3, the working station on the right side of the figurehas its longitudinal direction running in the Y-direction of the gridstructure's lower track layout, such that this working station has itslongitudinal rails 38 a, 38 b lying in the Y-direction and its crossrails 40 a-40 f lying the X-direction. The first and second cross-rails40 a, 40 b of the working station's lower track form parallel, in-lineextensions of a first pair of X-direction rails of the grid structure'slower track layout, and the last and second last 40 e, 40 f cross railslikewise form parallel, in-line extensions of a second pair ofX-direction rails of the grid structure' lower track layout.Accordingly, a robotic storage/retrieval vehicle can ride along a pairof X-direction rails of the lower track layout through the uncladdedopen space 34 between the two upright frame members at the ends of theserails at the outer side of the grid structure at which the workingstation resides, and onto the first and second cross rails 40 a, 40 b atthe entrance spot S_(EN) of the working station. At this entrance spot,the robotic storage/retrieval vehicle transitions from an X-directiontravel mode into a Y-direction travel mode, and can then travel alongthe working station's longitudinal rails 38 a, 38 b in the Y-directionto the exit spot S_(X) of the working station. Here, the roboticstorage/retrieval vehicle then transitions back into its X-directiontravel mode to ride atop the last and second last cross rails of theworking station back onto the second pair of X-direction rails of thelower track layout of the grid structure through the uncladded openspace 34 between the upright frame members at the ends of these rails.

The working station on the left side of FIG. 3 has its longitudinaldirection running in the X-direction of the grid structure's lower tracklayout, such that this working station has its longitudinal rails 38 a,38 b lying in the X-direction and its cross rails 40 a-40 f lying theY-direction. The first and second cross-rails 40 a, 40 b of the workingstation's lower track form parallel, in-line extensions of a first pairof Y-direction rails of the grid structure's lower track layout, and thelast and second last 40 e, 40 f cross rails likewise form parallel,in-line extensions of a second pair of Y-direction rails of the gridstructure's lower track layout. Accordingly, a robotic storage/retrievalvehicle can ride along a pair of Y-direction rails of the lower tracklayout through the uncladded open space 34 between the two upright framemembers 12 standing upright from the ends of these rails at the outerside of the grid structure at which the working station resides, andonto the first and second cross rails 40 a, 40 b at the entrance spotS_(EN) of the working station. At this entrance spot, the roboticstorage/retrieval vehicle transitions from the Y-direction travel modeinto the X-direction travel mode, and can then travel along the workingstation's longitudinal rails 38 a, 38 b in the X-direction to the exitspot S_(X) of the working station. Here, the robotic storage/retrievalvehicle then transitions back into its Y-direction travel mode to rideatop the last and second last cross rails of the working station backonto the lower track layout of the grid structure on the second pair ofX-direction rails through the uncladded open space 34 between theupright frame members at the ends of these rails.

Between the second cross rail 40 b and second last cross rail 40 e ofeach working station are a plurality of intermediate spots between theentrance and exit spots. The illustrated example features threeintermediate spots, but this number may vary. One of these intermediatespots, particularly the second last spot immediately neighbouring theexit spot S_(X) in the illustrated example, is designated as an “accessspot” S_(A) at which the robotic storage/retrieval vehicle is accessibleby the human or robotic worker via an access opening 52 penetratingthrough the top panel 50 of the chute from the countertop surface 50 athereof into the interior space of the chute. Accordingly, when thestorage/retrieval vehicle travelling longitudinally through the chutearrives and stops at the access spot S_(A), the worker can interact witha storage unit carried atop said storage/retrieval vehicle, for exampleto pick one or more individual items from the storage unit as part of anorder fulfilment process withdrawing such items from the grid structure,to instead remove the entire storage unit from the storage/retrievalvehicle as part of such an order fulfillment process, or to insteadplace one or more individual items into the storage unit as part of arestocking process replenishing the grid structure. Alternatively, arestocking process may involve directing an empty one of the roboticstorage/retrieval vehicles (i.e. a vehicle currently unoccupied by astorage unit) to the access spot of the working station to pick up astorage unit from the worker through the access opening 52.

The working station 18 is equipped with a hand-sensing mechanism toprotect human workers from potential injury as they interact with thestorage/retrieval vehicle through the access opening 52. With referenceto FIG. 6A, first and second sensor bars 54, 56 are affixed to theunderside of cover panel 50 of the working station in positions lyingalong opposing perimeter edges of the access opening. The sensor barscarry optical beam emitters and receivers in opposing relation to oneanother on the two bars 54, 56 so that beams emitted by the emitters arereceived by the opposing receivers unless the beam is interrupted, forexample by insertion of a workers hand(s) into the access opening 52. Asopposed to emitters and receivers on opposing sides of the accessopening, the sensor configuration may employ emitters and receivers onthe same side of the opening, and reflectors on the opposing sidethereof. The sensor bars communicate, through wired or wirelessconnection, with a computerized control system that wirelesslycommunicates with the fleet of robotic storage/retrieval vehicles tocontrol conveyance thereof throughout the grid structure to performvarious tasks (picking, restocking, etc.). Continuity of the hand sensorbeams generates a “safe” signal, whereas interruption of the sensorbeams generates a “stop” signal. Transmission by the computerizedcontrol system to a storage/retrieval vehicle of any movementinstruction that commands said storage/retrieval vehicle to move into orout of the access spot of a working station is conditional on detectionof a “safe” signal from the hand sensing mechanism of that workingstation. This way, no robotic storage/retrieval vehicle is ever drivenalong the lower track of the working station while a worker's hand isinside the chute.

In addition to serving a safety purpose, the hand sensing mechanism mayalso be operable for quality assurance purposes helping ensure humanworking accuracy in their picking tasks. For a given order for which apredetermined quantity of items is known to be required from a givenstorage unit, the computerized control system can count the number oftimes the optical beams are broken while that storage unit is present atthe access spot, thus representing a count of how many times the workershands were inserted through the access opening to access the storageunit an pull a respective item therefrom. The system compares thehand-insertion count against the predetermined quantity of items knownbe required from that storage unit, and only permits thestorage/retrieval vehicle on which that storage unit is carried todepart the access spot of the working station once the hand-insertioncount has reached the predetermined item quantity associated with thatstorage unit.

The hand sensing mechanism also serves as a height-check on the storageunit to ensure that not items therein are protruding notably upward fromthe top of the storage unit, as such protruding items will break thelight curtain formed by the optical beams, and thus prevent departure ofthe storage/retrieval vehicle and the storage unit thereon from theaccess spot until the protrusion is rectified. This helps ensure thatthe storage/retrieval vehicle will not attempt to re-enter the storagegrid with one or more items protruding from the storage unit andinterfering with the available travel spaces between the frameworkcomponents of the grid structure.

While FIGS. 4 through 6 show the inner longitudinal rail 38 a as part ofthe isolated working station, it will be appreciated that this rail isshared with the lower track layout of the grid structure when theworking station is installed at the grid structure. With reference toFIG. 3, the inner longitudinal rail 38 a of the working station on theright side of the figure is an in-line section of the Y-directionperimeter rail 26 at the respective side of the grid structure's lowertrack layout 28. The outer rail of that working station lies parallel tothe Y-direction perimeter rail of the grid structure's lower tracklayout, and the cross-rails of the working station connect theY-direction perimeter rail 26 of the lower track layout to the outerlongitudinal rail 38 b of the working station at positions in-line withand joined to the X-direction rails of the lower track layout. Likewise,the inner longitudinal rail 38 a of the working station on the left sideof the figure is an in-line section of the X-direction perimeter rail 24at the respective side of the grid structure's lower track layout. Theouter rail 38 b of that working station lies parallel to the X-directionperimeter rail of the grid structure's lower track layout, and thecross-rails of the working station connect the X-direction perimeterrail of the lower track layout to the outer longitudinal rail 38 b ofthe working station at positions in-line with and joined to theY-direction rails of the lower track layout.

The lower track of each working station is thus an extension trackconnected to the lower track layout of the three-dimensional gridstructure in a position running alongside the lower track layout toallow seamless transition of the robotic storage/retrieval vehiclesbetween the three-dimensional grid and the working station situatedoutside the two-dimensional footprint occupied by the upper and lowertrack layouts and the columns and shafts spanning therebetween. Thetransition of the vehicles between the lower track layout of thethree-dimensional grid and the working station takes place via theworking station entrance S_(EN) situated at one end of the workingstation's lower track and the working station exit S_(X) situated at anopposing second end of the working station's lower track. By way of thecomputerized control system, the robotic storage/retrieval vehicles aredriven through the working stations in a unidirectional manner from thededicated entrance to the dedicated exit, which allows multiple vehiclesto be queued inside the working station, thus reducing trafficobstruction on the lower track layout of the three-dimensional grid. Inthe illustrated example, the use of separate entrance and exit spots andinclusion of one or more intermediate spots in each working stationbetween the entrance and exit spots thereof increases this internalqueueing capacity of each working station.

However, the use of separate entrance and exit spots, inclusion of oneor more intermediate spots between the entrance and exit, and placementof the access opening at a dedicated spot other than the entrance orexit spots are optional features, and may be omitted altogether or invarious combinations. For example, in one alternative embodiment, thelower track of the working station may be as simple as two cross-railsextending from the lower track layout to define a single spot over whichthe access opening 52 resides, thus serving as an entrance, exit andaccess point of the working station all at one singular track spot. Therobotic storage/retrieval vehicle would ride forwardly onto thissingle-spot extension track in the X or Y direction perpendicular to theperimeter rail at the side of the lower track layout, receiveinteraction with the worker through the access opening, and then exitthe working station in a reverse direction back onto the lower tracklayout of the three-dimensional grid. Accordingly, the extension trackneed not necessarily be elongated along the perimeter of the lower tracklayout of the grid structure like in the illustrated embodiment, and theenclosure need not necessarily be an elongated chute having spaced apartentrance and exit points at longitudinally spaced locations of theworking station's lower track.

FIG. 7 schematically shows an overhead plan view of one of the workingstations, and a neighbouring area of the lower track layout of thethree-dimensional grid. As with the working station lower track, thesquare area denoted between two adjacent X-direction rails and twoadjacent Y-direction rails of the lower track layout is referred to as arespective “spot” therein. Each spot underlying a respective down-shaftof the three-dimensional grid is designated as a landing spot S_(LND) atwhich the robotic storage/retrieval vehicles land on the lower tracklayout after having travelled vertically downward through thedown-shaft. Each spot underlying a respective up-shaft at the outerperimeter the three-dimensional grid is designated as a launching spotS_(LCH) from which the robotic storage/retrieval vehicles travelupwardly through the up-shaft to the upper track layout. The spot in thelower grid that neighbours the entrance spot S_(EN) of the workingstation 18 is referred to as an emergence spot S_(EM) from which therobotic travel vehicle exits the lower track layout of thethree-dimensional grid and enters the working station 18 at the entrancespot thereof. The spot in the lower grid that neighbours the exit spotS_(X) of the working station 18 is referred to as a re-entry spot S_(R)from which the robotic travel vehicle re-enters the three-dimensionalgrid from the exit spot S_(X) of the working station. Arrows in thefigure show the travel path followed by a robotic storage/retrievalvehicle, first travelling outward from the emergence spot of the lowertrack layout into the entrance spot of the working station, thentravelling longitudinally through the access spot for interaction withthe worker, before moving longitudinally into the exit spot and thentransitioning back into the lower track layout at the re-entry spotthereof.

One or both of the departure and re-entry spots may be a multi-purposespot, for example also serving as a landing or launching spot under arespective down-shaft or up-shaft, as shown in the illustrated examplewhere the re-entry spot is also a landing spot. All other spots in thearea of the lower track layout neighbouring the working station underlierespective storage columns of the grid in which the storage units areshelved. These spot serve as available parking spots S_(P) in which arobotic storage/retrieval vehicle carrying a respective storage unit canbe selectively parked after landing on the lower track layout at thelanding spot S_(LND) at the bottom of the down-shaft from which therobotic storage/retrieval vehicle retrieved said storage unit in theevent that there's another robotic storage/retrieval vehicle that isdestined for the same working station and whose travel to said workingstation has been assigned a greater priority ranking than the roboticstorage/retrieval vehicle being parked. Selection by the computerizedcontrol system of a particular spot at which to park one of thestorage/retrieval vehicles may be based on an available least-distancetravel path to the working station entrance from a particular one of thedesignated landing spots at which the parking storage/retrieval vehiclearrived at the gridded lower track layout.

Accordingly, the computerized control system responsible for assigningtasks to the robotic storage/retrieval vehicles and controllingnavigation thereof through the three-dimensional grid and workingstations can orchestrate arrival of a group of occupied vehicles (i.e.vehicles carrying respective storage units thereon) to the assignedworking station for which those storage units are destined in a sequencethat doesn't necessarily match the sequence in which the tasks wereassigned (i.e. the assignment sequence), the sequence in which thosestorage units were retrieved (i.e. the retrieval sequence) from theirrespective storage locations, the sequence in which the occupiedvehicles landed at the lower track layout (i.e. the landing sequence),or the sequence in which the occupied vehicles initially arrived into avicinity of the emergence spot adjacent the assigned working station(i.e. the arrival or approach sequence).

In one illustrative example, a picking operation is executed by thecomputerized control system, and involves assigning a first group of oneor more vehicles to retrieve one or more respective storage units eachcontaining a different item for a first customer order and deliver saidstorage units to a particular working station, and a second group of oneor more vehicles assigned to retrieve one or more storage units eachcontaining a different item for a second customer order for delivery tothe same working station. Due to differences in travel distance from theinitial location of each vehicle to the assigned working station via anavailable retrieval location at which a storage unit containing theappropriate item is stored (of which there may be multiple options, inwhich case priority may be given based on shortest overall travel pathfrom the robotic storage/retrieval vehicle's current location to theassigned working destination via the different retrieval locationoptions), vehicles from the two groups may arrive at the lower trackwith their retrieved storage units and approach the assigned workingstation in a mixed order. Here, the computerized control system canassign priority rankings on which to sequence the entry of the twogroups of vehicles into the working station, and instruct lower priorityvehicles to park themselves at currently unoccupied parking spots of thelower track layout.

The assigned priority ranking may be based at least partly on a “groupeddelivery” basis so that all items for one order are delivered prior toany item for the other order. Further weighting may be based on a “firstlanding” or “first arrival” basis, where the first vehicle landing atthe lower track layout or approaching the assigned working stationdictates which of the two vehicle groups is prioritized over the otherin the “grouped delivery” sequence, or on an “order priority” basiswhere the orders are ranked by priority due to size (i.e. picking largerorders before smaller ones), shipment destination (picking ordersdestined for more remote destination before more local destinations),delivery deadlines, customer types, shipment vehicle availability, etc.So, depending on the ranking criteria selected, all items of the firstorder may be delivered to the access spot of the working station beforeany item of the second order, or vice versa, regardless of theparticular sequence in which the two orders were received by the system.Alternatively, a large order requiring a high number of storage unitsfor complete fulfillment may have its queue of robotic storage/vehiclesinterrupted by one or more robotic storage/retrieval vehicles assignedto a small order in order to pick the entire small order at the workingstation before returning to continued picking of the larger order.

By using the very same grid structure in which the storage units arearrayed and by which the robotic vehicles navigate the storage array,this internally performed sequence orchestration enables complexsequencing or sortation during order picking operations while avoidingthe space and material inefficiencies associated with prior arttechniques, such as space intensive sortation conveyors, where theretrieval step is performed by one fleet of machines, and then sortationis performed downstream at a second stage of different machinery orequipment type, before delivering sorted items to assigned workingstations situated remotely of the storage structure.

While the forgoing example specifically uses dedicated up-shafts,dedicated down-shafts, and designated parking spots specifically on thelower track layout for the purpose of selectively parking vehicles afterstorage unit retrieval on their way to assigned lower level workingstations without interfering with flow of other unparked vehicles movingthrough the three dimensional grid, it will be appreciated that otherlocales in the three dimensional grid may be used to temporarily parkretrieved storage units during the orchestration of sequenced deliveryto the working stations. Accordingly, any of the square spots betweenthe X and Y direction rails of the upper track layout may likewise beused as a temporary parking spot for occupied vehicles during deliverysequence orchestration, just as they may be used to park inactivevehicles awaiting activation by way of operational assignment andinstruction from the computerized control system. In such instance, thespots overlying the up-shafts and down-shafts are preferably reserved asdrop-down spots for entry to the down-shafts and climb-out spots forexit from the up-shafts, and thus not employed for temporary parkingpurposes so as not to hinder traffic flow of unparked vehicles throughthe grid. Likewise, the sequenced delivery orchestration may employparking of vehicles at any level in the down-shafts and/or up-shafts forthe purpose of delaying the arrival of such parked vehicles to theworking stations in view of higher priority rankings assigned to theother occupied vehicles, though again, it may be preferable to avoidsuch obstruction to shaft travel by other vehicles. While selectembodiments have specific up-shafts dedicated to only upward trafficflow of the robotic storage/retrieval vehicles and separate down-shaftsdedicated to only downward traffic flow, it will be appreciated thatother embodiments need not restrict each shaft to a particular directionof traffic flow. Accordingly, the spot on the lower track layout beneathsuch a two-way shaft would serve as both a launching spot and landingspot, and the spot on the upper track layout above the two-way shaftwould serve as both a drop-down and climb-out spot for that shaft.

While the forgoing examples focus on picking operations used to fulfillan order by delivering storage units containing items for that order toa working station where a human or robotic worker can remove such itemsfrom the storage units and compile them into a shipping container fordelivery to a customer, the working stations can also be used forre-stocking or order buffering operations, where items are placed intothe storage unit presented by the robotic storage/retrieval vehicle atthe access spot of the working station, from which the roboticstorage/retrieval vehicle then re-enters the grid to place that storageunit in an available storage location in the three-dimensional grid. Inthe re-stocking operation, the items placed in the roboticstorage/retrieval vehicle-carried storage unit are new inventory itemsof a type not previously stored in the structure, or inventoryreplenishment items replacing previously picked items.

An order buffering operation first involves a picking operation, inwhich the computerized control system assigns and instructs a group ofstorage/retrieval vehicles to retrieve different storage unitscontaining a particular collection of items required to fulfill anorder, and to carry the retrieved items in their respective storageunits down to the gridded lower track layout and onward to the entranceof the working station assigned to this buffering operation. As theassigned group of vehicles move through the working station, the workerextracts one or more items of the order from the storage unit on eachvehicle when said vehicle arrives at the access spot of the workingstation, and these extracted items are amalgamated together in order toform a full or partial fulfillment of the order.

This fully or partially fulfilled order is placed into a container ofcompatible size with the storage spaces in the three-dimensional gridstructure. This container may the same as the rest of the storage units,for example an openable/closeable storage bin, or may be a shipmentcontainer of different type from the storage units (e.g. cardboardshipping box, optionally sealed closed and having a shipping labelalready placed thereon, for example if the amalgamated order contentsfulfill the entire order). The computerized controller sends an unloadedvehicle to the same working station, where the container with theamalgamated order contents is placed atop this vehicle at the accessspot of the working station. The computerized controller then sends thisorder-carrying vehicle back into the three-dimensional grid structurewith instructions to store the fully or partially fulfilled order in anavailable storage location in the three-dimensional grid structure. Thesame three-dimensional storage grid used to store inventory items cantherefore also be used to buffer partially prepared or fully-readyshipments until a later date or time, for example a future pickup timeat which a shipping vehicle is expected to arrive to pick up a fullycompleted order for delivery, or in the case of a partially fulfilledorder requiring additional items currently not in stock, a future timeat which the out of stock inventory will be replenished to enablecompletion of the order.

When it comes time for the pickup or inventory replenishment, abuffered-order retrieval operation is performed by the computerizedcontrol system, sending a robotic storage/retrieval vehicle to retrievethe order container from its storage location, and deliver the ordercontainer to one of the working stations, for retrieval of thecontainer, or the individual items contained therein, through the accessopening of the working station. If the buffered order was only a partialorder, then the previously missing items are then amalgamated with theretrieved items, either by addition to the same container if useable asa shipment container, or by amalgamation into a new shipping container.

Having summarized the novel working stations of the present invention,novel uses thereof, and novel use of the three-dimensional gridstructure itself for workstation delivery sequencing and orderbuffering, attention is now turned to other points of novelty in thethree-dimensional grid structure, robotic vehicle fleet and cooperativeoperation therebetween.

FIG. 8 illustrates an isolated section of the lower track layout of thethree-dimensional grid structure, with parallel first and secondlongitudinal rails 60 a, 60 b running in the X-direction of the lowertrack layout, and a parallel set of additional cross-rails 62 a-62 fperpendicularly interconnecting the first and second longitudinal rails60 a, 60 b at regularly spaced intervals therealong in the Y-directionof the lower track layout. As mentioned above, a respective spot of thelower track layout is denoted by the square area between the twolongitudinal rails and each adjacent pair of cross-rails 62 a-62 f. Thecross-rail on the same side of each spot (on the right side of each spotin the illustrated example) carries a visually detectable locationmarker 66 thereon at a mid-point of the cross-rail's topside. Thedetectable location marker may be applied as a separate sticker orlabel, or etched into the rail of the track itself. Each roboticstorage/retrieval vehicle carries a scanner 66 on a side of the roboticstorage/retrieval vehicle that matches the side of the track spots onwhich the location markers 64 are positioned. The scanner comprises animage capture device with a downwardly angled field of view oriented tocapture imagery of the marked cross-rails as the roboticstorage/retrieval vehicle travels the lower track layout. The field ofview is aimed so that the frame size thereof at the marked topsides ofthe rails exceeds the size of the detectable markers. The scanner andthe location markers are positioned relative to one another such thatwhen the robotic storage/retrieval vehicle is properly centered betweenthe two longitudinal rails and two cross-rails bounding a given spot ofthe lower track, the respective location marker 66 on one of thecross-rails will occupy a predetermined subregion of the scanner's fieldof view (e.g. a central area thereof). As the robotic storage/retrievalvehicle arrives at a targeted destination spot of the lower tracklayout, the scanner captures images from its current field of view and asoftware module executed by a local computer processor of the roboticvehicle compares the position of the location marker within the largerviewing frame of the scanner to check fore agreement between the markerposition in the viewing frame and expected viewing frame sub-region inwhich the marker is expected. So where the sub-region is a central areaof the viewing frame, the software is checking whether the marker isproperly centered in the viewing frame. The relative agreement ordisagreement thus reflects the relative alignment between the roboticstorage/retrieval vehicle and the targeted spot on the lower tracklayout.

As described in Applicant's aforementioned prior PCT application, therobotic storage/retrieval vehicle 14 features a set of X-directionwheels 68 on two opposing sides of the robotic storage/retrievalvehicle, and a set of Y-direction wheels 70 on the other two opposingsides of the robotic storage/retrieval vehicle. The X-direction wheels68 are raiseable and lowerable relative to a frame or chassis of therobotic storage/retrieval vehicle into an out of engagement with theX-direction rails of the track layout, just as the Y-direction wheels 70are raiseable and lowerable relative to a frame of the roboticstorage/retrieval vehicle into an out of engagement with the Y-directionrails of the track layout. Raising of the X-direction wheels out ofcontact with the X-direction rails is performed when the roboticstorage/retrieval vehicle is to travel in the Y direction by drivenrotation of the Y-direction wheels on the Y-direction rails, whileraising of the Y-direction wheels out of contact with the Y-directionrails is performed when the robotic storage/retrieval vehicle is totravel in the X direction by driven rotation of the X-direction wheelson the X-direction rails.

FIG. 8 shows the example where the robotic storage/retrieval vehicle 14is riding in the X-direction of the lower track layout toward a targeteddestination spot thereon, and is scanning the location markers on theY-direction rails as it does so. Each location marker may embody ascannable code containing a unique ID of the respective spot itdesignates within the two-dimensional grid map of the lower tracklayout, whereby this unique ID together with detected alignment of thelocation marker of the targeted destination spot can be used to bothconfirm arrival of the robotic storage/retrieval vehicle at the correcttargeted destination spot, and achieve proper centering of the roboticstorage/retrieval vehicle on this spot. Such alignment ensures that 1)the robotic storage/retrieval vehicle doesn't interfere with travel ofother vehicle's travelling in the other direction through neighbouringspots in the track layout; and 2) the robotic storage/retrieval vehicleis properly aligned with the vertical shaft above it if the targeteddestination spot is a launching spot from which the roboticstorage/retrieval vehicle is intended to travel upwardly through theshaft above it.

The engagement of wheels on opposing sides of the roboticstorage/retrieval vehicle with the corresponding rails of the lowertrack layout automatically ensures alignment of the roboticstorage/retrieval vehicle on the targeted spot of the lower track layoutin the track direction perpendicular to these rails. So in theillustrated example of FIG. 8, the X-direction wheels are engaged withthe X-direction rails, thus automatically aligning the roboticstorage/retrieval vehicle with the targeted spot in the Y-direction.During arrival of the robotic storage/retrieval vehicle at the targetedspot in the X-direction, the scanner captures imagery from its viewingframe and the software executed by the local processor on the roboticstorage/retrieval vehicle checks the position of the location markerimage within the viewing frame, and uses any deviation between theactual and expected location marker position in the viewing frame asfeedback signals to dynamically adjust the drive signals to the motorsof the X-direction wheels so as to drive the robotic storage/retrievalvehicle into properly centered alignment on the targeted spot. The samealignment procedure is used to provide feedback-governed control overthe Y-direction wheels when travelling into a targeted spot in theY-direction. Since the robotic storage/retrieval vehicles never changeorientation on the track layout, the particular selection of which setof rails the markers are placed on (either X-direction or Y directionrails) is of no consequence, provided that the scanner is placed on theappropriately cooperative side of each vehicle.

In addition to such adjustment of the vehicle position as it arrives atthe targeted spot on the track layout, earlier dynamic adjustment of thevehicle's travel may take place upstream of such arrival by scanning theother markers past which the vehicle is travelling on its way to thetargeted spot beneath the targeted shaft. The original travelinstructions assigned and transmitted to the storage/retrieval vehicleby the computerized control system are based on actual physical distanceto the targeted shaft based on the known grid dimensions of thestructure. Where the vehicle is travelling through more than onepass-through spot to reach the targeted grid spot below the targetedshaft, the scanner can perform a scan as it moves through eachpass-through spot use the results to dynamically correct the travelinstructions on the fly to account for differences between theoriginally assigned travel distance and the true-remaining traveldistance from the vehicle's current location to the targeted spot, thusco-ordinating more precisely aligned arrival of the storage/retrievalvehicle at the targeted spot to avoid or reduce the need for fine-tuningof the alignment during final arrival at the targeted spot.

While the illustrated embodiment employs static location markers locatedin the gridded three-dimensional structure at fixed positions relativeto the targetable spots on the lower track layout, and moving scannerscarried on the travelling storage/retrieval vehicles, this arrangementmay be reversed by having statically positioned scanners in the gridstructure and detectable markers on the robotic storage/retrievalvehicles, though having the scanning and associated image processingcarried out on the robotic storage/retrieval vehicle whose wheels arebeing controlled is likely preferable. While the forgoing description ofthe scanner/marker alignment confirmation tool is made with reference tothe lower track layout to ensure that a vehicle is properly aligned at atargeted launching spot of the lower track layout before the roboticstorage/retrieval vehicle is lifted up into the shaft above suchlaunching spot, the same tool may also be employed on the upper tracklayout to ensure alignment of a vehicle at a targeted drop-down spotovertop of a respective shaft before lowering of the roboticstorage/retrieval vehicle down into said shaft.

FIGS. 10 through 15 illustrate one of the robotic storage/retrievalvehicles at a launching spot S_(LCH) of the lower track layout of thethree-dimensional grid structure. A majority of the grid is omitted forillustrative purpose, leaving only the four rails of the lower tracklayout that delimit this particular launching spot (of which oneX-direction rail is labelled 60, and one Y-direction rail is labelled62), the four support legs 30 supporting the rails at the intersectionpoints therebetween at the corners of the launching spot, and two of thefour upright frame members 12 that stand upright from the four cornersof the launching spot to define the four corners of the respectivevertical up-shaft above the launching spot. The other two upright framemembers are omitted to provide improved visibility of the roboticstorage/retrieval vehicle to demonstrate interaction thereof with anovel lifting mechanism 72 for raising the storage/retrieval vehicle upinto the overlying up-shaft.

The lifting mechanism 72 is seated atop the same ground surface as thesupport legs 30 of the lower track layout within the rectangularfootprint of the launching spot. Shown in isolation from the lower tracklayout in FIGS. 16 through 19, the lifting mechanism 72 features a baseframe having four vertically upright corner legs 74 interconnected byhorizontal cross-braces 76, and an upper panel 78 mounted atop the baseframe at the top ends of the corner legs 74. A lifting platform 80resides above the upper panel 78 of the base frame, and is movablycarried thereon in a raiseable/lowerable manner by a suitable actuator,which in the illustrated example is an electric linear actuator 81 whoseelectric motor 82 is mounted to the underside of the base frame's upperpanel with the output rod 84 of the actuator reaching upwardly through acentral opening in the upper panel to connect to the underside of thelifting platform. Accordingly, extension of the linear actuator raisesthe lifting platform upwardly from the upper panel, and retraction ofthe linear actuator lowers the lifting platform back down into contactor close adjacency to the upper panel of the base frame. A set of fourlinear guide rods 86 are affixed to the underside of the liftingplatform near the corners thereof, and pass down through a set ofbushings or bearings in the upper plate of the base frame for slidingmovement upwardly and downwardly through the upper plate duringextension and retraction of the linear actuator. The rod guides thushelp stabilize the lifting platform to maintain a horizontally levelorientation thereof.

The base frame is of a lesser height than the lower track layout so thatthe upper panel 78 of the base frame resides at an elevation below thetopsides of the rails of the lower track layout, and for exampleslightly below the undersides of these rails so that when the liftingplatform is in the lowered position adjacent the upper panel of the baseframe, it doesn't protrude above the rails of the lower track layout. Inthe lowered position of the lifting platform, the roboticstorage/retrieval vehicles can thus travel freely over the launchingspot in either track direction. Mounting brackets 88 reach outward fromthe upper panel of the base frame of the lifting mechanism at two ormore sides thereof and are fastened to the rails of the lower tracklayout, for example at the undersides thereof, thus fixing the positionof the lifting platform in a properly squared relation to the griddedtrack layout and in properly centered position within the square area ofthe launching spot.

The lifting mechanism is communicable with the computerized controlsystem via wired or wireless connection thereto. When a roboticstorage/retrieval vehicle travelling along the lower track layoutreaches a targeted launching spot under an up-shaft through which therobotic storage/retrieval vehicle is destined to travel, and isaccurately aligned with the up-shaft using the above described locationmarkers and cooperating scanners, the wireless transceiver of therobotic storage/retrieval vehicle responsible for communication thereofwith the computerized control system signals said system of theconfirmed arrival of the robotic storage/retrieval vehicle at thetargeted launching spot. In response to this, the computerized controlsystems sends an activation signal to the lifting mechanism, in responseto which the actuator 80 thereof is activated in the extension directionto raise the lifting platform 80 up into contact with an underside ofthe robotic storage/retrieval vehicle's frame or chassis just above therails of the lower track layout. With the weight of the roboticstorage/retrieval vehicle now borne by the lifting mechanism rather thanby riding of the robotic storage/retrieval vehicle's conveyance wheelson the rails of the lower track layout, the conveyance wheels of therobotic storage/retrieval vehicle are drawn inwardly in an inboarddirection to reduce the robotic storage/retrieval vehicle footprint to areduced size capable of entering the shaft so that the pinion wheels canengage with the rack teeth on the upright frame members at the cornersof the up-shaft to enable climbing of the storage/retrieval vehicletherethrough. Only one lower set of rack teeth 90 is shown the bottomsegment 32 of one of the two illustrated upright frame members in FIGS.10 through 15, but it will be appreciated that such rack teeth areprovided on all eight inwardly facing sides of the four upright framemembers of the up-shaft, and span a substantially full height of theshaft to near the upper track layout.

After or during such retraction of the wheels, further extension of thelifting mechanism actuator is performed to lift the roboticstorage/retrieval vehicle into a raised position in which the teeth ofthe robotic storage/retrieval vehicle's pinion wheels are brought intoengagement or immediate adjacency with lowermost rack teeth on theupright frame members of the grid structure, at which point activationof the robotic storage/retrieval vehicle's pinion wheels initiatesclimbing of the robotic storage/retrieval vehicle upwardly through theup-shaft of the grid structure. The lifting mechanism, being powered bya mains power supply, thus reduces the overall energy load consumed bythe on-board power supplies of the storage/retrieval vehicle in itstravel from the lower track layout up the upper track layout, as thestorage/retrieval vehicle's on-board power supply is not used to liftthe robot up to an engagable position with the rack teeth.

To maintain the robotic storage/retrieval vehicle in alignment with theup-shaft during lifting, the lifting platform and underside of thevehicle chassis may have matable male and female features laid out inmatching pattern to one another to automatically align with one anotherwhen the vehicle is properly centered on the launching spot of thetrack, whereby raising of the lifting platform mates the male/femalefeatures thereon with the matching female/male features on the undersideof the vehicle chassis. The mated features prevent the vehicle chassisfrom sliding around on the lifting platform as it is raised. In oneexample, four male nipples protrude upwardly from the topside of thelifting platform near the outer corners thereof to mate with four matingrecesses in the underside of the vehicle chassis.

FIG. 20 shows one of the robotic storage/retrieval vehicles 14 and astorage unit 92 receivable on the robotic storage/retrieval vehicle fortransport thereby within the three-dimensional grid structure and theworking stations. In the illustrated example, the storage unit to andfrom which smaller individual items can be inserted and removed is anopen-top tray, though as mentioned elsewhere herein above, anopenable/closeable box, bin or tote may alternatively be used. In otherembodiments, the storage unit may be the packaging of an individualitem, as opposed to a container for storing multiple items therein. Inother embodiments, where the grid dimensions and working stations are oflarger scale, a storage unit may be a pallet on which one or items arereceived, whether one relatively large individual item, or a pluralityof items. In the example of multiple palleted items, the items may bedistributed among multiple containers (e.g. boxes, trays, bins or totes)placed or stacked on the pallet, with one or more items stored in eachsuch container.

As disclosed in Applicant's aforementioned prior PCT application, therobotic storage/retrieval vehicle 14 features an upper support platform94 on which the storage unit 92 is receivable for carrying by therobotic storage/retrieval vehicle 14, and which may feature a rotatableturret 96 surrounded by a stationary outer deck surface 98. As disclosedin Applicant's aforementioned prior PCT application, the turret may onceagain have an extendable/retractable arm (not shown), which togetherwith the rotatable function of the turret allows pulling of storageunits onto the support platform and pushing of storage units off thesupport platform at all four sides of the robotic storage/retrievalvehicle so that each vehicle can access a storage unit on any side ofany shaft in the three-dimensional grid structure. In the presentlyillustrated embodiment, the turret and deck surface are shown insimplified form without detail for illustrative simplicity.

The turret and surrounding deck surface collectively define a squarelanding area atop which the storage unit is seated when carried on therobotic storage/retrieval vehicle 14. This landing area is equal orsimilar in size and shape to the underside of each storage unit in thethree-dimensional grid structure, as shown by FIG. 21 where the seatedposition of the storage unit occupies an entirety of the landing area.For the purpose of ensuring that the storage unit is fully received andproperly aligned on the landing area of the robotic storage/retrievalvehicle, the upper support platform 94 has a set of load status sensors100 situated in close proximity to the outer perimeter thereof at spacedapart positions along said perimeter. In the illustrated example, theload sensors are optical sensors recessed in to the upper surface of thelanding area, and provided in a quantity of four, each positionedproximate a respective one of the four outer corners of the landingarea. As part of a loading routine pulling a storage unit onto therobotic storage/retrieval vehicle from a storage location in thethree-dimensional grid using retraction of the extendable/retractablearm, the local processor on the vehicle then checks the status of thefour load status sensors for detected presence of the underside of thestorage unit above the sensor. A positive detection signal from all fourload status sensors thus confirms the presence of the storage unit atall four corners of the landing area, thereby confirming that thestorage unit is fully received on the landing area and is in properlysquared alignment therewith.

One embodiment uses reflective optical sensors for load statusdetection, where light energy transmitted by an optical beam emitter ofthe sensor is reflected off the underside of the storage unit back to anoptical receiver of the sensor when the storage unit is presentthereover, thus successfully determining said presence. Time of flightcalculation (i.e difference in time between emission of an optical pulseand detection of the reflected optical pulse) may be used todifferentiate between reflection off the underside of a storage binseated on the landing area of the robotic storage/retrieval vehicle vs.reflection off another surface further away. It will be appreciated thatsensor types other than optical sensors may be employed, for exampleincluding limit switches mechanically actuated by contact with theunderside of the storage unit, or magnetic sensors actuated by presenceof cooperating magnetic elements emitting detectable magnetic fields atthe underside of the storage unit. However, optical sensors may bepreferable to avoid moving parts or need for magnetic integration orother specialized configuration of the storage units.

As disclosed above, the three-dimensional grid structure used to storeinventory items in an order fulfillment center can also be used tobuffer fully or partially completed orders within the same inventorystorage grid structure. FIG. 22 illustrates a separate three-dimensionalsortation/buffering grid that can supplement an inventory storage gridof the type shown in FIG. 2. For example, palletized incoming supplyinventory can be depalletized and induced into the inventory storagegrid of FIG. 2, from which orders are then picked and packaged intoshipping containers, which are then induced into the sortation/bufferinggrid structure 200 of FIG. 22. the sortation/buffering grid structure200 features the same three-dimensional framework as the inventorystorage grid, thus having matching upper and lower track layouts, andthe array of upright frame members therebetween for delimiting storagecolumns and upright shafts between the two track layouts to enable afleet of the robotic storage/retrieval vehicles to horizontally traverseeach track layout, and vertically traverse the shafts between the twotrack layouts to access the shelved storage locations therebetween.However, the storage locations in the sortation/buffering grid 200contain previously packed shipment containers containing the orderspicked from the inventory storage grid. The robotic fleet is once againwirelessly controlled via a central computerized control system, forexample the same computerized control system shared by the inventorystorage grid.

In the illustrated example of FIG. 22, the upper track layout of thesortation/buffering grid 200 is served by a plurality of intake stations202 co-operably installed therewith for the purpose of loading incomingshipping containers 204 onto robotic storage/retrieval vehicles on theupper track layout. Each intake station may comprise a conveyor 206 onwhich a series of incoming shipping containers can be queued forinduction into the sortation/buffering grid 200, with an outlet end ofeach conveyor elevated slightly above the upper track layout of thesortation/buffering grid 200 at the outer perimeter thereof by anelevated distance equal to or slightly exceeding the heights of therobotic storage/retrieval vehicles 14. This way, the outlet of eachintake conveyor 206 resides at or above an upper horizontal referenceplane occupied by the landing areas of the robotic storage/retrievalvehicles when riding on the upper track layout. The intake conveyor canthus slide or drop an incoming shipping container onto the landing areaof one of the robotic storage/retrieval vehicles situated at a pickupspot aligned with the outlet end of the intake conveyor at the outerperimeter of the upper track layout.

One or more intake stations may be provided at any one or more perimetersides of the upper track layout, though as illustrated, the intakestations may all reside at a common side of the upper track layoutthat's nearest to an on-site inventory storage grid from which thepacked shipping containers are arriving, or nearest to one or moreintermediate packing stations at which order items amalgamated at theinventory storage grid working stations are subsequently packaged beforebeing forwarding on to the sortation/buffering grid 200. However, itwill be appreciated that the two grids need not necessary be located ina shared facility.

The lower track layout of the sortation/buffering grid 200 is served bya plurality of output stations 208 co-operably installed therewith forthe purpose of unloading outgoing shipping containers 210 off of roboticstorage/retrieval vehicles on the lower track layout. Each outputstation may comprise a conveyor 212 on which a series of outgoingshipping containers can be queued for transfer to a further downstreamlocation of the facility, for example a final packing area or loadingbay at which the containers will be loaded onto a shipping vehicle whenavailable. An inlet end of each output conveyor 212 is situated at orslightly below a lower horizontal plane in which the landing areas ofthe robotic storage/retrieval vehicles reside when riding on the lowertrack layout. This way, a robotic storage/retrieval vehicle at adrop-off spot situated at the outer perimeter of the lower track layoutin alignment with the inlet end of the conveyor can slide or drop ashipping container from said robotic storage/retrieval vehicle onto theinlet end of the output conveyor. One or more output stations may beprovided at any one or more perimeter sides of the upper track layout.The illustrated example features output stations on at least twoopposing sides of the lower track layout, for example to respectivelyfeed a pair of loading bays or packing areas optionally situated onopposing sides of the sortation/buffering grid 200.

Each incoming shipping container may be picked up from one of the intakestations by a robotic storage/retrieval vehicle assigned to this pickuptask by the computerized control system, and then carried to anavailable (i.e. currently unoccupied) storage location in thesortation/buffering grid 200 via the respective shaft from which thisstorage location is accessible, and left at this storage location forlater retrieval. Alternatively, instead of commanding the assignedrobotic storage/retrieval vehicle to store the incoming shippingcontainer, the computerized control system may command the roboticstorage/retrieval vehicle to deliver the shipping container directly toone of the output stations in view of a need or availability at theloading bay or packing area for that shipping container on an urgentbasis.

In selecting between these storage and direct output options for thepicked-up shipping container, the computerized control system mayconsult an order priority ranking of an order associated with thatshipping container, relative to other orders whose constituentcontainers have already been inputted to the sortation/buffering grid200. Additionally or alternatively, if the picked-up shipment containeris only a partial component of a larger overall order, then thedetermination of whether to store the shipping container or deliver itstraight to an output station is based at least partly on whether theother shipment containers fulfilling the remainder of the larger overallorder are also present, or imminently expected, at thesortation/buffering grid 200. If the entire order is present orimminently present, and there aren't any other orders of higher priorityranking, then the currently picked-up container may be put directlythrough to the appropriate output station to which the order is assignedby the computerized control system. The other constituent containers ofthat same order are retrieved from respective storage locations in thesortation/buffering grid 200, if already present therein, and deliveredto that same assigned output station, or are assigned for imminentpickup and straight delivery to that output station if said otherconstituent containers are currently at, or imminently expected at, theinput stations.

One particular example of a useful application for the combination ofthe two three dimensional grids is aisle-based or similar location-basedkitting operations, for example where different retail items destinedfor a retailer are picked in groups from the inventory storage gridaccording to a particular aisle section or other identifiable sub-regionof the retailer's store layout for which the particular items aredestined. The different groups are packed into different shippingcontainers, and then fed individually into the sortation/buffering gridfor temporary storage (i.e. buffering) as each such picked group ofitems is picked and packaged. Exiting the inventory storage grid, theconnected working stations thereof, or subsequent packing station(s)located further downstream from the inventory storage grid at differenttimes, the shipping containers arrive at the sortation/buffering grid atstaggered points in time, with one or more initially received containerspotentially arriving much earlier than a subsequently received remainderof said containers, and so the earlier received packages are temporarilystored (i.e. buffered) in the sortation/buffering grid, at least untilsuch time as the remainder of containers are received by or imminentlyapproaching the sortation/buffering grid. At such time, thepreviously-buffered initially-received shipping containers are retrievedfrom their respective storage locations in the sortation/buffering grid200 and delivered to a common output station by one or more of therobotic storage/retrieval vehicles for amalgamation (e.g. palletization)into the completed order ready for shipment to the retailer.

This however, is only one non-limiting example of the usefulness of thesortation/buffering grid 200, the use of which is not specificallylimited to use with a inventory storage solution specifically using thethree-dimensional grid structure employed in the present invention andApplicant's aforementioned prior PCT application. Also, aisle-basedkitting for retailers is only one example, and non-retail customerssimilarly having an aisle-based or similarly mapped organizationallayout with different identifiable sub-regions may likewise benefit fromkitted delivery. This may include manufacturers with organized storagefor incoming raw materials or pre-fabricated componentry from outsidesuppliers, where kitted shipment containers are destined for suchon-site manufacturer storage, from which the raw materials orpre-fabricated componentry are distributed to one or more manufacturingstations in the facility. The kitting approach may also be used wherethe manufacturing stations themselves are the different identifiablesub-regions for which the kitted materials or componentry are destinedaccording to the supply needs of such stations, whether these stationsare different stages within one product line, or full or partialassembly stations for two different product lines.

In another example, such manufacturing facilities could have theinventory storage grid of FIG. 2 on site for kitting of raw materialsand/or componentry, either with or without the downstreamsortation/buffering grid 200, to feed kit-populated storage units to themanufacturing stations at the same facility.

Since various modifications can be made in my invention as herein abovedescribed, and many apparently widely different embodiments of samemade, it is intended that all matter contained in the accompanyingspecification shall be interpreted as illustrative only and not in alimiting sense.

The invention claimed is:
 1. A storage system comprising: a griddedthree-dimensional structure comprising: in a lowermost level of saidgridded three-dimensional structure, a gridded lower track layout thatoccupies a two-dimensional area and on which one or morestorage/retrieval vehicles are conveyable in two directions over saidtwo-dimensional area; and a plurality of storage columns residing abovethe gridded lower track layout in spaced distribution over thetwo-dimensional area of said lower track layout, each column comprisinga plurality of storage locations arranged one over another and sized toaccommodate placement and storage of storage units therein; and aplurality of upright shafts residing above the gridded lower tracklayout in spaced distribution over the two dimensional area of saidlower track layout, each storage column being neighboured by arespective one of the upright shafts through which the storage locationsof said storage column are accessible by the one or morestorage/retrieval vehicles to place or remove the storage units to orfrom said storage locations of said storage column; and at least oneworking station residing alongside the gridded three-dimensionalstructure and outside the two-dimensional area of the lower track layoutover which the storage columns and upright shafts are distributed, saidworking station being joined to the gridded lower track layout by anextension track thereof by which said one or more storage/retrievalvehicles are conveyable between said working station and said lowertrack layout, whereby conveyance of the storage units between thestorage locations and the working station is performable entirely bysaid one or more storage/retrieval vehicles; wherein said extensiontrack is connected to the gridded three-dimensional structure at saidgridded lower track layout in the lowermost level of said gridded threedimensional structure, said extension track runs through said workingstation and comprises a plurality of discrete spots therein that areeach sized to be respectively occupiable by an individual one of saidstorage/retrieval vehicles, said working station comprises a countertopthat resides overhead of the extension track, and said plurality ofdiscrete spots include an access spot overtop of which said countertopis penetrated by an access opening through which a carried storage uniton said one of the storage/retrieval vehicles is accessible when parkedat said access spot, and at least one additional spot that is fullycovered by said countertop.
 2. The storage system of claim 1 wherein theextension track of the working station is an only vehicle-ridable trackof said working station, and is connected to the griddedthree-dimensional structure solely at the gridded lower track layout ofthe lowermost level thereof.
 3. The storage system of claim 1 whereinsaid extension track is connected to the lower track layout of thegridded three-dimensional structure at two opposing ends of saidextension track, whereby each storage/retrieval vehicle can traverse theextension track in a direction emerging from the griddedthree-dimensional structure at a first end of the extension track andre-entering the gridded three-dimensional structure at a second end ofthe extension track, and the system further comprises at least oneprocessor configured to generate signals instructing one of the storageretrieval vehicles to enter the working station at said first end of theextension track, to thereafter perform sequential advancement throughsaid discrete spots toward the second end of the extension track, totemporarily park at the access spot during said sequential advancementthrough said discrete spots, and to thereafter exit the working stationand re-enter the gridded three-dimensional structure at said second endof the extension track.
 4. The storage system of claim 1 wherein theextension track, at all sides thereof other than an inner side at whichsaid extension track is connected to the gridded lower track layout, isfully enclosed.
 5. The storage system of claim 1 wherein the extensiontrack passes through the working station from an entrance situated at oradjacent one end thereof to an exit situated at or adjacent an opposingend thereof, and the system comprises at least one processor configuredto generate signals instructing one of the storage retrieval vehicles toenter the working station at said entrance, to thereafter performsequential advancement through said discrete spots toward the exit, totemporarily park at the access spot during said sequential advancementthrough said discrete spots, and to thereafter exit the working stationand re-enter the gridded three-dimensional structure at said exit. 6.The storage system of claim 1 wherein said at least one working stationcomprises a plurality of working stations each linked to the griddedlower track layout by a respective extension track.
 7. The system of anyclaim 1 comprising at least one processor configured to organizesequenced delivery of a group of storage units from thethree-dimensional gridded structure to the access spot of the workingstation, including: (a) generating signals to instruct a plurality ofstorage/retrieval vehicles to retrieve the storage units from respectivethe storage locations; (b) identifying, from among the plurality ofstorage/retrieval vehicles, a first storage/retrieval vehicle of ahigher ranked sequence priority than a second storage/retrieval vehicle;(c) commanding said first storage/retrieval vehicle to advance to, andpark at, said access spot on the extension track; (d) commanding saidsecond storage/retrieval vehicle to advance to, and temporarily park at,a nearby one of the discrete spots that is situated near said accessspot; and (e) upon departure of said first storage/retrieval vehiclefrom said access spot, commanding said second storage/retrieval vehicleto advance to, and park at, said access spot.
 8. A storage systemcomprising: a plurality of storage/retrieval vehicles; a griddedthree-dimensional structure comprising: a gridded track layout thatoccupies a two-dimensional area and on which the storage/retrievalvehicles are conveyable in two directions over said two-dimensionalarea; a plurality of storage columns residing above or below the griddedtrack layout in spaced distribution throughout the two-dimensional areaof said track layout, each column comprising a plurality of storagelocations arranged one over another and sized to accommodate placementand storage of storage units therein; and a plurality of upright shaftsresiding above or below the gridded track layout in spaced distributionwithin the two-dimensional area of said track layout, each storagecolumn being neighboured by a respective one of the upright shaftsthrough which the storage locations of said storage column areaccessible by the storage/retrieval vehicles to place or remove thestorage units to or from said storage locations of said storage column;and at least one working station residing outside the two-dimensionalarea of the track layout within which the storage columns and uprightshafts are distributed; wherein: conveyance of the storage units betweenthe at least one working station and the storage locations in thegridded three-dimensional structure is performed solely by saidstorage/retrieval vehicles; said working station is joined to thegridded track layout by an extension track thereof by which saidstorage/retrieval vehicles are conveyable between said working stationand said lower track layout; said extension track comprises a pluralityof discrete spots that are located within the working station and areeach sized to be respectively occupiable by an individual one of saidstorage/retrieval vehicles, and that include an access spot and one ormore additional spots; said working station, at least at all sidesthereof other than an inner side of the working station at which saidextension track is connected to the gridded track layout, is fullyenclosed at each of said one or more additional spots; said workingstation, at said access spot, has an access opening that penetrates intothe working station to enable access to a carried storage unit on saidone of the storage/retrieval vehicles when parked at said access spot;and the system further comprises at least one processor configured toorganize sequenced delivery of a group of storage units from thethree-dimensional gridded structure to the access spot of the workingstation, including: (a) generating signals to instruct the plurality ofstorage/retrieval vehicles to retrieve the group of storage units fromrespective the storage locations; (b) identifying, from among theplurality of storage/retrieval vehicles, a first storage/retrievalvehicle of a higher ranked sequence priority than a secondstorage/retrieval vehicle; (c) commanding said first storage/retrievalvehicle to advance to, and park at, said access spot on the extensiontrack; (d) commanding said second storage/retrieval vehicle to advanceto, and park at, a nearby one of the discrete spots that is situatednear said access spot; and (e) upon departure of said firststorage/retrieval vehicle from said access spot, commanding said secondstorage/retrieval vehicle to advance to, and park at, said access spot.9. A storage system comprising: a plurality of storage/retrievalvehicles; a three-dimensional structure comprising a three-dimensionalarray of storage locations sized to accommodate placement and storage ofstorage units therein, said storage vehicles being configured tonavigate within said three dimensional structure and place and retrievesaid storage units to and from said storage locations; and at least oneworking station to which retrieved storage units from the storagelocations are conveyable by said storage/retrieval vehicles; whereineach working station comprises an enclosure through which saidstorage/retrieval vehicles are conveyable on a track that comprises aplurality of discrete spots that are located within said enclosure andare each sized to be respectively occupiable by an individual one ofsaid storage/retrieval vehicles, said plurality of discrete spotsincluding an access spot and one or more additional spots, of which onlysaid access spot is equipped with an access opening in said enclosurethrough which a carried storage unit on said one of thestorage/retrieval vehicles is accessible when said vehicle is parked atsaid access spot, while said one or more additional spots are each fullyenclosed, at least at all sides of the working station other than aninner side thereof at which said track connects to the three-dimensionalstructure; and wherein the system further comprises at least oneprocessor configured to organize sequenced delivery of a group ofstorage units from the three-dimensional gridded structure to the accessspot of the working station, including: (a) generating signals toinstruct the plurality of storage/retrieval vehicles to retrieve thegroup of storage units from respective the storage locations; (b)identifying, from among the plurality of storage/retrieval vehicles, afirst storage/retrieval vehicle of a higher ranked sequence prioritythan a second storage/retrieval vehicle; (c) commanding said firststorage/retrieval vehicle to advance to, and park at, said access spot;(d) commanding said second storage/retrieval vehicle to advance to, andpark at, a nearby one of the discrete spots that is situated near saidaccess spot; and (e) upon departure of said first storage/retrievalvehicle from said access spot, commanding said second storage/retrievalvehicle to advance to, and park at, said access spot.
 10. The storagesystem of claim 9 wherein said one or more additional spots comprise anentrance spot and an exit spot between which the access spot resides,and the at least one processor is configured to: during commandment ofeach of the first and second storage/retrieval vehicles: commandentrance thereof to the working station at the entrance spot; thereaftercommand sequential advancement through said discrete spots toward theexit spot; during said sequential advancement, command temporary parkingat said access spot; and thereafter command exit from the workingstation and re-entry to the three-dimensional structure via said exitspot.
 11. The storage system of claim 9 wherein the access openingresides in overhead relation to the access spot, and said workingstation comprises a countertop that fully covers said one or moreadditional spots, but that is penetrated by the access opening.